(i) Field of the Invention
The subject of the present invention is a device for confining gas leaks from a gas cylinder.
(ii) Description of the Related Art
When a gas cylinder containing compressed or liquefied toxic gases under pressure has a leak which is impossible to stop (leaks at the collar, for example), there are two solutions. Either the leak is significant and cannot be brought under control, in which case the area where the leaking cylinder is located is evacuated and a safety perimeter is marked out, or the leak is not very great and a pressure-resistant confinement system is then used. The objective is to seek to completely contain the leak in an outer container. The leaking gas cylinder is put in a pressure-resistant confinement chamber.
Various types of construction have thus been developed and marketed. One embodiment consists of a confinement container in which an entire leaking cylinder can be placed.
This device relies on the idea of containing the toxic gases escaping from the cylinder. This is a heavy pressure-resistant system which is difficult to use. This confinement system is expensive, which limits its mass production. The time required to fetch it from the place where it is stored to the site of the incident may furthermore be quite long, the time to set up the confinement system proper requiring some ten minutes.
It should furthermore be noted that this device cannot be used with unstable gases such as acetylene. Likewise, its use with spontaneously inflammable gases (SiH.sub.4, B.sub.2 H.sub.6, etc.) is not recommended.
It is known from U.S. Pat. No. 5,086,804 to produce a smaller container which screws onto the top of the leaking cylinder.
The container according to this second known embodiment has the drawback that it may be geometrically incompatible (thread diameter, screw pitch, etc.).
It is known from U.S. Pat. No. 4,955,404 to screw a bonnet onto the cylinder, which bonnet is then filled with a fusible substance (metal alloy) which, by solidifying, stops the leak. Various systems have also been proposed which aim to contain the leak by applying a counterpressure to the adapter or body of the cylinder, the stop device proper being held in position by a number of metal chains. The aforementioned embodiment, of confinement of the leak by applying a counterpressure to the adapter, has the drawback that the chains are not easy to manipulate.
However, not one of these safety systems can be used to take action in a very short space of time, a few minutes, on a leak which cannot be stopped but which is not out of control.